Lightweight spherical bearings for jogging strollers

To imitate the natural arm movement when running, the stroller is equipped with two arm levers like a cross trainer. To generate the pendulum motion, the JogAlong engineers originally connected the two levers at the rotary axis with shafts and a differential gear. In order to cope with the high torque and keep the diameter of the gears as small as possible, they had to be made of metal.

This solution was too complicated, too heavy and too expensive. The challenge was to find another way to manage the many degrees of freedom between the levers and the connecting link, to simplify the connection and to make it as light and cost-effective as possible.

After numerous further tests, the solution was finally found at igus®: igubal® spherical plain bearings of the EGLM series, mounted between the levers and a second connecting piece.

The bearing enables three degrees of freedom to be realized simultaneously: the spherical outer diameter allows the connecting piece to swivel in relation to each lever; the cylindrical inner bore of the sphere is used for both an axial sliding degree of freedom and a rotational degree of freedom. In this way, the complexity of the assembly and therefore the costs and weight can be significantly reduced. Furthermore, the bearings are dry-running and maintenance-free.